The present invention relates to the display of video data on an oscilloscope, and more particularly to a multi-standard video option for an oscilloscope that automatically detects the standard of an input video signal and sets up the oscilloscope to display the input video signal.
In many television facilities where versatility is required at low budget costs, an oscilloscope that is used to do general electrical waveform analysis is also used to perform the functions of a high performance television waveform monitor. Such instruments include the 2400 Series Four Channel Oscilloscopes with Option 05, manufactured by Tektronix, Inc. of Beaverton, Oregon, United States of America. These instruments use a bi-level triggering system to generate a high true pulse equal to the duration of the horizontal sync pulse of a composite sync signal derived from an input video signal. This generated pulse is a digital signal that is used to trigger the oscilloscope at an appropriate horizontal interval. These instruments also are able to differentiate between the even and odd fields of an interlaced television signal, or determine that the television signal is a non-interlaced signal in the absence of even and odd fields.
With the current development of high definition television (HDTV) there exist three HDTV protocols, HDTV 1050/59.94, 1125/60 and 1250/50, actively being pursued in the television industry. Rather than a bi-level horizontal sync pulse as in the NTSC, as shown in FIG. 1, and PAL standard television protocols, the new HDTV protocols incorporate a new tri-level horizontal sync pulse, as shown in FIGS. 2 and 3.
What is desired is a multi-standard video option for an oscilloscope that automatically detects the standard of an input video signal, either conventional or HDTV, interlaced or non-interlaced, and sets up the oscilloscope to present an appropriate display.